How to Kill a Rhododendron Stump

Cut stump treatment is most effective when the rhododendron is actively growing.

Rhododendrons (Rhododendron spp.) are evergreen or deciduous shrubs or small trees that grow throughout U.S. Department of Agriculture plant hardiness zones 4 through 10, although the growing ranges of individual species or cultivars are usually much smaller. These plants are often prized for their large, colorful blossoms and deep green foliage, but in some situations they are undesirable because of their poisonous nature and an ability to both produce a large quantity of seed and spread to crowd out other vegetation. Cutting the rhododendron down removes the bulk of the aboveground portion of the specimen, but these plants will resprout readily, calling for chemical treatment.

1

Recut the stump if it was not cut within the last 30 minutes or so. Use a saw or lopping shears, depending on the size of the stump, and make the cut completely flat and as close to the soil surface as possible, exposing live tissue.

2

Brush a nonselective herbicide such as glyphosate, triclopyr or imazapyr, diluted according to manufacturer directions for cut stump applications, onto the freshly cut stump surface.

3

Inspect the stump area for new shoots regularly and spray these emerging sprouts with a nonselective herbicide such as glyphosate as soon as you notice them. Also monitor a broader area for seedlings if the rhododendron was mature and produced viable seed, and pull up or spray these unwanted seedlings promptly.

Things You Will Need

Saw or loppers

Nonselective herbicide

Paintbrush or foam applicator

Spray applicator, if needed

Warnings

If the undesirable rhododendron stump's roots might be connected to the root system of a desirable rhododendron, chemical application could injure the desirable plant. In this case, the only treatment option is to dig out the stump and as much of the root system as possible.

Use any herbicide carefully and according to manufacturer recommendations. Nonselective herbicides can injure or kill any plants that they come into contact with.